The tax aims to encourage the shoppers to use reusable bags to reduce the amount of trash in landfills.

"We've seen in other communities, both in the Midwest as well as on the East Coast and the West Coast, who have put a tax like this in place and see a significant reduction in the usage of disposable bags," said Alexandra Holt, the city's budget director.

Some shoppers say they support the idea if it helps the environment.

"My philosophy is if it's for good, I don't mind paying a little bit more," said customer Felipe Weffer.

Others do not: "I think it's ridiculous. I just don't understand it. Why do we have to pay for bags?" said customer Daphne McNeil.

The city will also give away free, reusable "ChiBags" at seven CTA locations during the evening commute

The tax was approved in November as part of the city's budget. City officials also repealed a ban on plastic bags starting Jan. 1.

The so-called "checkout bag tax" applies to all Chicago retailers, not just large grocery chains.

Stores are preparing for the new tax.

At Jewel-Osco, a variety of reusable grocery bags were for sale including canvas bags and others lined to keep food cold.

There are some exceptions to the bag tax. For example, bags for loose bulk foods like fruits and vegetables or wrapped frozen foods or foods that could contaminate other items.

Julia Sarron has already been bringing her own bags to the store for years

"Environmentally, it seemed better to buy something that is reusable like these bags," Sarron said.

At Whole Foods, they have been encouraging shoppers to use reusable bags for a long time.

"This is something we and our shoppers have always believed in as our commitment to not only our local communities, but also to the environment," said Allison Phelps, a Whole Foods spokesperson.

Whole Foods, Jewel and several other chains will be giving away a limited number of reusable bags on Wednesday.